Draw-twisting method and yarn tension adjusting apparatus



June 20, 1967 E. BUCHER 3,325,985

DRAW-TWISTING METHQD AND YARN TENSION DJUSTING APPARATUS Filed Jan. 24,1964 6 Sheets-Sheet l E. BUCHER -,ulne 20, 1967 DRAW-TWISTING METHOD ANDYARN TENSION ADJUSTING APPARATUS 6 Sheets-Sheet 2 Filed Jan. 24,11964 (5n fik-@QJ J. fweef June 20, 1967 E. BUCHER v 3,325,985

DRAW-TWISTING METHOD AND YARN TENSION ADJUSTING APPARATUS Filed Jan. 24,1964 6 Sheets-Sheet 3 Inventor:

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June 20, 1967 E. BUCHER 3,325,985

DRAW-TWISTING METHOD AND YARN TENSION ADJUSTING APPARATUS Filed Jan. 24,1964 l 6 Sheets-Sheet 4 Inventor: 'gf/'4f BMA@- June 20, 1967 E. BUCHER3,325,985

DRAW-TWISTING METHOD AND YARN TENSION ADJUSTING APPARATUS Filed Jan. 24,1964 6 Sheets-Sheet r Fig. 6c

t1 t3 la `lune 20, 1967 E. BUCHER 3,325,935

DRAW-TWISTING METHOD AND YARN TENsloN ADJUSTING APPARATUS Filed Jan. 24,1964 6 Sheets-Sheet 6 F Fig. 8

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United States Patent O 3,325,985 DRAW-T'WlSTING METHOD AND YARN TENSIONAEJUSTING APPARATUS Erich Bucher, Goppingen, Wurttenrberg, Germany,assignor to Zinser-Textilrnaschinen Gesellschaft mit beschrankterHaftung, Ebersbach (Fils), Germany Filed Jan. 24, 1964, Ser. No. 340,083Claims priority, application Germany, Jan. 30, 1963,

9,884 31 Claims. (Cl. 57-93) The present invention relates to adraw-twisting method and to a yarn 1 tension :adjusting apparatus whichis used in carrying out the method of the invention. More particularly,the present invention relates to an arrangement according to whichsingle yarns consisting of a synthetic material are wound on a rotatingbobbin after being drawn out 2 and then twisted by means of a travelerrunning around a twisting ring.

Known draw-twisting apparatus of this type uses bobbins rotated byspindles at a constant speed. The speed of the traveler is substantiallysmaller at the beginning of a winding operation than at the end of thewinding operation due to the fact that the dia-meter of the packagewound on the bobbin is continuously increased and that the twist givento the yarn by the twisting operation is not substantial. The speed ofthe traveler must not exceed a certain upper limit since excessivetraveler speeds result in damage to the traveler and also in unduly hightension of the yarn during the twisting and winding operation. High yarntension results in undesired stretching of the yarn which reduces theusefulness of the twisted yarn. Due to these reasons, known draw-twisteror drawtwisting apparatus provides a constant rotary speed of thespindle which is only so high that the traveler speed at the end of thewinding operation when the diameter of the package is greatest,substantially corresponds to the maximum speed permissible for thetraveler. During the first part of the winding operation, the travelerspeed is consequently substantially below the permissible upper speedlimit so that the draw-twis-ting machine does not operate at fullcapacity, and the yarn is not wound at the highest permissible speedduring the first part of each winding operation by which -a package iswound on a spindle.

It is one object of the present invention to overcome this disadvantageof known draw-twisting machines, and to provide a method and apparatusfor winding a yarn on a bobbin at the highest desired winding speedduring the entire winding operation.

Another object of the present invention is -to rotate the bobbin, andthe spindle carrying the bobbin, at a varying speed to compensate forthe increase of the winding speed and of the traveler speed caused bythe gradually increasing diameter of the wound package.

Another object of the present invention is to maintain the yarn tensionof a yarn wound in a draw-twister or draw-twisting machine on a bobbinat predetermined desired values during the entire winding operation.

Another object of the invention is to control the twisting `and windingoperation in such a manner that the yarn tension varies during thewinding operation in accordance with a predetermined function.

Another object of the invention is to control the rotary speed of thebobbin during the winding operation in accordance with a predeterminedprogram representing a 1The expression yarn to be interpreted in theentire specification und claims as a Continuous filament or a plurahtyof filaments in forni of a continuous lainent yarn.

2 The expression drawn out to be interpreted in the entire specificationand claims as stretching or drawing the filament or filament yarn to anincreased length.

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desired function according to which the rotary speed of the bobbin is tovary during the winding operation.

Another object of the invention is to control the rotary speed of thebobbin in accordance with the actual tension of the yarn during thetwisting and Winding operation.

Another object of the present invention is to wind a yarn on a bobbin ina draw-twisting machine in such a manner that yarn portions located insuperimposed layers of the pack-age have different predeterminedtensions.

With these objects in View, the present invention relates mainly to anarrangement in which the tension of a yarn which is wound on a bobbin ina draw-twisting machine is regulated or controlled in accordance with apredetermined function.

In such an arrangement, it is possible to vary the tension of a yarndurin-g a winding operation in such a manner as required by thetechnological and physical properties of the yarn, and by the propertiesdesired of the wound package.

Particularly, the function, which may be graphically represented, can bedetermined in such a manner that undesired high yarn tensions, which maybe produced by a stretching of the yarn during the twisting operation,are prevented for all practical purposes.

For example, the function may be selected in such a manner that the yarntension is slightly below the maximum permissible yarn tension which isgiven by the physical and technological properties of the respectiveyarn. It is, however, a prerequisite for such a determination of theyarn tension that the speed of the traveler does not exceed the maximumpermissible speed. Consequently, the maximum yarn tension must bedetermined in view of the maximum permissible traveler speed.

The function according to which the yarn tension is to be controlled,may be at least during part of the winding operation maintained at aconstant level.

It has been found that the function can be selected in such a mannerthat the feeding speed of the drawingout device through which the yarnpasses before being wound on a bobbin, and there-by the entire output ofthe draw-twisting machine can be increased without any detrimentaleffects on the yarn package. The feeding speed may be maintainedconstant during each winding operation. This corresponds to a variationof the rotary speed of the spindle supporting the bobbin, which resultsin diterently twisted yarn portions, but it has been found that suchdifferences in twist are without any practical consequences as comparedwith the advantage of increased production of the draw-twisting machine,and the improved technological properties of the drawn-out and twistedyarn.

In accordance with the present invention, the function according :towhich the yarn tension varies can be selected in such a manner thatcertain undesired properties of the finished package Iare avoided. Forexample, in packages wound in accordance with the prior art, arelaxation or shrinking of the yarn lin the package takes place inaccordance with the position of yarn portion on Ia smaller or largerdiameter of the package. In accordance with the invention, suchdifferences can be compensated partly or completely by controlling orregulating the yarn tension during the winding operation.

In accordance with one embodiment of the invention, the yarn tension iscontrolled or regulated in accordance with a predetermined functionduring the winding operation, and particularly during the second half ofthe winding operation.

During the rst half of the winding operation, the yarn tension may besubstantially maintained at a high constant value, and in many cases itis desirable to reduce this yarn :tension during the rst part of thewinding operation.

By controlling the yarn tension in this manner at least during part ofthe winding operation, particularly at the beginning, the presentinvention accomplishes the result that the outwardly lying yarn loops ofthe package will not slip out of position when the yarn is wound off thepackage. In packages wound in accordance with the prior art, theoutermost windings of the package frequently slip across, or `betweenother windings, since the yarn is 4wound at high tension. Furthermore,the cornparatively soft consistency of the inner part of the woundpackage, caused by low yarn tension at the beginning of the windingoperation in accordance tothe prior art, permits the entering of outerwindings between adjacent inner windings. In accordance with the presentinvention, the yarn tension is high particularly at the beginning of thewinding operation when the inner part of the packagel is being wound, sothat `the latter is correspondingly more rigid and consequently will notpermit the entering of outer yarn windings between adjacent windings ofthe inner part.

In accordance with a preferred method and apparatus according to thepresent invention, the yarn tension is controlled in accordance with apredetermined program, which is advantageously represented by a programcarrier, such as a card read out by program controlled means. The yarntension is continuously sensed during the winding operation, and thesensed actual yarn tension compared with a desired yarn tensionrepresented by the program. As long as the actual value and the programrepresented desired value of yarn tension differ, the rotary speed ofthe bobbin carrying spindle is varied in such a manner that thedifference between the value is reduced. This method permits raparticularly exact regulation of the yarn ytension in accordance with apredetermined function represented by the program.

If it is desired to have the yarn tension constant, then the regulationin accordance with a function represented by a program can be omitted,and the sensed actual yarn tension compared with Ia constant desired andselected yarn tension. Such comparison of the actual yarn tension with adesired yarn tension following a function represented by a program, orbeing constant, is preferably carried out by an electronic comparisondevice.

In thefevent that the regulation of the yarn tension takes place inaccordance with a function represented by a program, the respectivefunction constitutes a variation of the desired tension during thewinding time. Since information regarding the actual yarn tension iscompared with information represented by a program, this type ofregulation may be considered as a feedback regulation.

A draw-twisting machine has a great number of spindles which are allsimultaneously rotated. In accordance with the present invention, it ispreferred to determine the yarn tension only at a single winding stationby a sensing means engaging one yarn wound on a bobbin, and to controlthe rotary speed of all spindles of the machine in accordance with therotary speed determined by the apparatus of the invention for a singlespindle.

Since the yarn tension is partly dependent on the friction between thetraveler and the twisting ring, and since such friction may vary atdifferent twisting spindles, it follows that the yarn tension may bedifferent at different spindles. However, it has been found that suchdifferences of the yarn tensions at `different twisting stations arecomparatively insignificant so that it is sufficient to regulate orcontrol the yarn tension -of all twisting stations in accordance withthe values determined for one characteristic twisting station.

In accordance with another embodiment of the invention, the yarn tensionis not sensed, but the rotary speed of the spindle is regulated orcontrolled in accordance with a program which has been empirically foundto result in yarn tension following 'a desired function, and in apackage having the desired properties. In this elmbodiment as well, thesmall frictional differences between the individual twisting stationsare of no consequence, and all twisting stations and spindles of themachine can be controlled in accordance with a program represented by asingle program carrier.

The yarn tension discussed above is the tension of the yarn portionbetween the drawingout device and the bobbin during a twistingoperation. It has been found that this tension is not constant over theentire length of the respective yarn portion. The yarn tension betweenthe drawing-out device and the travelery is Adifferent from theV yarntension between the traveler and the bobbin. in accordance with thepresent invention it is preferred to regulate or control the rotaryspeed of the spindles in accordance with the yarn tension prevailingbetween the drawing-out devicer and the traveler, and more particularlybetween the drawing-out device and the thread guide located in the axisof the 'bobbin and spindle.

Such an arrangement has particularly` good results concerning a highfeeding speed of the drawing-out device, and good technologicalproperties of the drawn-out and twisted yarn.

However, if it is desired` that under no circumstances a certain maximumtension between drawing-out device and bobbin is exceeded, which mayoccur with very fine delicate yarns, then the yarn tension betweenbobbin and traveler may be sensed for controlling the winding andtwisting operation.

If it is not desired to regulate the yarn tension, but to influence therotary speed of the spindle depending on the program, the rotary speedof the spindle can be regulated or controlled in accordance with theprogram. If the rotary spindle speed is to vbe regulated, informationregarding the actual spindle speed is fed back into comparison devicewhich also receives a signal corresponding to a desired rotary speed inaccordance with a program. Differences between the desired programrepresented speed and the actual speed of the rotary spindle, produce acommand signal by which the spindle speed is adjusted. Under certaincircumstances, it is not necessary to regulate the rotary speed ofthespindles in this manner, andy it is sucient to control the rotaryspeed in accordance with a program. In this event, the motor driving therotary spindles is adjusted in accordance with a program whichrepresents the preselected and desired rotary spindle speeds during eachmoment of the winding operation.

The function according to which the rotary speed of the spindles is to`be controlled by the program need be determined only once for aparticular batch of yarn. The yarn is wound on the bobbin of thedraw-twisting machine, while the yarn tension is regulated manually orautomatically .in such a manner that the yarn tension varies inaccordance with` a desired function. At the same time, the rotary speedof the spindle is continuously registered and recorded. On the basis ofthe recorded values of the rotary spindle speeds, the program functionfor the program regulation or progam control of the rotary spindle speedis determined. A record carrier is provided with records representingthe thus empirically determined function, and during future windingoperations, the rotary speed is controlled or regulated in accordancewith the function represented by the program. j Ring spinning machinesare known in which the speed of the spinning machine is controlledduring each spinning Operation in such a manner that peaks of the yarntension are avoided to prevent yarn breakage. However, this method inwhich the feeding speed of the drawing devices is varied at the same`time and together with the rotary speed of the spindles and with thefrequency of the spinning ring operation, and in the same ratio, cannotbe used with a draw-twister or a draw-twisting `machine of the type withwhich the present invention is con- Cerned in which a lament yarn isstretched or drawn out and wound to form a package on a bobbin. It hasbeen found by tests, that when the method of the prior art is used for amachine of the type with which the present invention is concerned, thetechnological properties of the stretched and twistedyarn aredetrimentally effected to such an extent that the yarn produced isuseless for most purposes. In contrast thereto, the method of thepresent invention improves the technological properties of the yarnsubstantially, and moreover causes a substantial increase of the outputof the machine.

In order to simplify the program control or program `regulation of therotary spindle speed, it is advantageous in certain cases to vary therotary spindle speed during at least part of the winding timesubstantially in accordance with a linear function. The arrangement isfurther simplified if the rotary spindle speed is maintained constantduring at least a part of the winding time.

In the preferred arrangement of the present invention, the rotaryspindle speed is reduced from a maximum value at the beginning of thewinding operation to a yminimum during the second half of the windingtime,

particularly between two thirds and three quarters of the Winding time.It is advisable to continuously reduce the rotary spindle speed, andparticularly advantageous to gradually reduce the rate at which thespindle speed is reduced so that the minimum spindle speed is approachedin an asymptotic manner. After the minimum spindle speed has beenreached and maintained for a time period, it is in many casesadvantageous to again increase the spindle speed at the end of thewinding time, either continuously or stepwise.

A method for draw-twisting yarn according to the present inventioncomprises the steps of drawing-out a yarn; rotating a bobbin and windingthe drawn-out yarn onto the bobbin so that a portion of the yarnsupplied to the 4bobbin is tensioned as a yarn package of increasingdiameter is formed on the bobbin; and automatically varying the rotaryspeed of the bobbin to maintain the tension of the yarn at predetermineddesired values while the diameter of the package increases. As explainedabove, the predetermined value may be a constant value, or a value-depending on a selected function achieving different and varying yarntensions during successive parts of the Winding operation.

According to one method of the invention, the yarn tension is sensed,and the sensed tension is compared with a predetermined desired tensionwhereupon the rotary speed of the bobbin is automatically regulateduntil the sensed tension is substantially equal to the predeterminedtension.

According to another method of the invention, the actual rotary speed ofthe bobbin is compared with a program representing a predeterminedcharacteristic function of a rotary bobbin speed over the winding time,and the rotary speed of the bobbin is regulated until the bobbin speedis substantially equal to the program represented speed at the samemoment. In accordance with another method of the present invention, therotary speed of the bobbin is automatically controlled in accordancewith anempirically determined program representing a selectedcharacteristic function of the rotary speed of the bobbin over thewindin g time.

An apparatus according to the invention comprises a drawing-out device;a rotary spindle; a twisting ring surrounding the spindle and a travelermounted for movement along the twisting ring; drive means rotating thespindle so that yarn supplied from the drawing-out device is wound up onthe bobbin to form a package of gradually increasing diameter; adjustingmeans, preferably including a servomotor controlling an electric motorforming part of the drive means to adjust the motor speed and therebythe rotary spindle speed; and operation controlling means forautomatically actuating the servomotor of the adjusting means so thatthe rotary speed of the spindle is varied 6 during the Winding operationin such a manner that the tension of the yarn between the bobbin and thedrawingout device is maintained at predetermined desired values whilethe diameter of the package increases during the winding operation.

In one embodiment of the invention, a sensing means for sensing the yarntension is provided and produces a signal proportionate to the sensedtension. The signal is supplied to a comparison device to which acomparison signal is supplied representing a desired tension. Thecomparison device produces a command signal representing the differencebetween the actual tension and the desired tension at the respectivemoment, and such signal is used to control the servomotor of theactuating means to adjust the rotary spindle speed.

The comparison signal may be constant and represent a constant desiredyarn tension, or may be varied in accordance with the functionrepresented by a program readout by a program controlled device from arecord carrying card.

In another embodiment of the invention, no sensing means is provided,and the comparison device is supplied with a signal representing theactual spindle speed which may be measured by a tachometric deviceproducing a signal whose voltage is proportionate to the actual rotaryspeed of the spindle and bobbin.

Instead of regulating the machine in this manner, it may be consideredsuliicient to control the machine directly in accordance with a program,and in this event the operati-on control means include a programcontrolled means producing signals representing a desired variation ofthe rotary speed of the spindle during a winding operation, and suchsignals are used for adjusting the drive motor of the spindle.

In the embodiment using a comparison device, information about theactual conditions is fed back to be compared with a desired valuerepresented by the program.

In one embodiment of the invention, the servomotor is controlled toadjust the position of the brushes of the motor of the drive means. Inanother embodiment of the invention, the motor of the drive means runsat constant speed, and a gradually variable transmission, providedbetween the motor and the spindles, is adjusted by the servomotor.

In the preferred embodiment of the invention a program card of plasticsynthetic material provided with ridges is used. However, a magneticrecord carrier or a perforated tape may be used as program carrier.

A program function represented by a program card is designed torepresent the rotary winding speeds during a single winding operation inwhich a complete package is wound on the bobbin of each spindle of themachine. A program function empirically determined, and a correspondingprogram carrier, can then be used again repeatedly for other windingoperations with empty bobbins replacing the ybobbins on which packageshave been completely wound, assuming that the yarn Wound during thesecond winding operation has the same technological and physicalproperties, and that the same type of package is desired.

However, it has been found that a program function determined for acertain yarn cannot only be applied t0 the yarn which was used forempirically determining the program function, but can be used for anumber of somewhat diiferent yarns having different yarn numbers orconsisting of a somewhat different material.

Generally, a number of record carriers with different empiricallydetermined programs will be available, and each program is suitable fora group of yarns which may be slightly different from each other.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe d best understood from the following description of specicembodiments when read in connection with the accompanying drawings, inwhich:

FIG. 1a is a perspective view illustrating a draw-twisting machine ordraw-twister provided with the yarn tension adjustingr apparatusaccording to one embodiment of the invention;

FIG. lb is a fragmentary perspective view illustrating the yarn tensionadjusting apparatus of the embodiment of FIG. la on a larger scale;

FIG. 2 is a fragmentary schematic perspective View illustrating theapparatus of the embodiment of FIGS. la and 1b, with parts of themachine omitted for the sake of clarity;

FIG. 3 is a fragmentary schematic perspective view illustrating amodified embodiment of the apparatus of the invention;

FIG. 4 is a fragmentary schematic perspective view illustrating anotherembodiment of the invention;

FIG. 5a is a perspective view illustrating 'a program carrying card usedin the l'apparatus of FIG. 2;

FIG. 5b is a cross-sectional view taken on line 5-5 in FIG. 5a;

FIG. 5c is a diagram illustrating the program represented by lthe cardshown in FIGS. 5a and 5b in the form of a graph;

FIG. 6a is a perspective view illustrating a program carrying card usedin ythe embodiment of FIG. 3;

FIG. 6b is a cross-sectional view taken on line 6-6 `in FIG. 6a;

FIG. 6c is a diagram illustrating the program of the` card shown inFIGS. 6a and 6b in the form of a graph;

FIG. 7 is a diagram illustrating variations ofthe rotary speed of thespindles automatically carried out in yaccordance with the presentinvention;

FIG. 8 is a diagram illustrating several yarn tensions automaticallyvaried Vand adjusted in accord-ance with the invention; and

FIG. 9 is a fragmentary schematic perspective view illustrating anotherembodiment ofthe invention.

Referring now to the drawings, Kand more particularly to FIGS. 1a, 1band 2, the draw-twisting machine shown in FIG. la comprises a hea-dstock 10, a tail stock 12, a base 14, and a series of twisting devicesarranged in two parallel rows at the front and rear of the machine. Themachine is particularly suited for the twisting of synthetic fibersrwhich are stretched or drawn out. Only a single yarn 11 is shown inFIG. 1a, but it will be understood that two rows of supply spools aredisposed on `a support, not shown, mounted on carrier rods 15. Each yarn11 is guided over a roller 16 and a plurality of guide roller means 13which assure the transport of the yarn which then passes between Iroller16 and a roller 30.

The yarn is then fed in the direction of the arrow A in FIG. 1 to aroller 18 and `another roller 20 over which the yarn is guided inseveral loops. The peripheral speed of roller 18 is greater than theperipheral speed of roller so that the yarn is stretched or drawn out bythe device 13, 16, 30, 18, 20, as is known to those skilled in the art.

The drawn-out yarn :is guided through a thread guide 47 in the form ofan eye disposed in the axis of a rotary twisting device 22 whichincludes a rotary spindley 24 having a vbobibin-supporting shaft 5l), yatwisting 4ring 35 surrounding a bobbin mounted on the spindle, and atraveler 21 mounted on the twisting ring 35. When the spindle isrotated, the bobbin rotates so that the yarn passing `through threadguide 47 and traveler 21 is wound in a package on the bobbin. Thesupport 75 moves twisting ring 35 in `:atxialdirection in areciprocating motion whose stroke is gradually reduced during thewinding operation so that the package has conical end portions, as isknown to those skilled inthe art.

Every spindle 24 has a spindle lbody 58 with la pulley portion 55. Inthe embodiment shown in FIG. 2, a belt 3 57 is guided over the pulleysof four spindles' and over a pair of guide rollers 51, 52, to a drivepulley 2S on drive shaft 27. Groups of spindles comprising two forwardand two rearward spindles are driven in this manner from drive shaft 27by driving devices generally indicated by a reference numeral 48.

Drive shaft 27 is driven by an electric drive motor 26 mounted in thehead stock 10 of the machine.

Another motor 36 is connected by a belt and pulley drive 38 to a shaft39 which drives the rollers 18 of the drawing-out device through pairsof bevel gears 43, 44.

Shaft 39 carries the bevel gears 43 for the drawing-out devices locatedin the front row, and a shaft 42 drives corresponding rollers of `therear row, as best seen in FIG. 2. A transmission gear arrangementgenerally indicated by reference numeral 40, is driven from a gear 39aon shaft 39 and transmits rotary motion to shaft 42, and 4the two shaftsby which the transportingV rollers 30 and 31 are driven.

In draw-twisting machines of the above described type according to theprior lart, `the spindles are rotated at a constant speed. During therst pia-rt of the winding operation, the speed of traveler 21 is lowerthan during the second `part of the winding operation due to the smallerdiameter of ythe wound package andthe low twist of the yarn. The speedof the traveler must not exceed a certain upper limit since very hightraveler speeds' result in breakage of the yarn, or at least inundesirably high tension of the yarn wound on the package. When thetension near the end of the winding operation of the package is toohigh, the yarn is stretched beyond its desired stretching previouslyproduced, and the quality and usefulness ofthe yarn will be impaired.Consequently, a constant spindle speed must be selected in such a mannerthat the speed of the traveler at the end of the winding operationcorresponds substantially to the maximal permissible upper limit. As aresult, the traveler speed is substantially below the permissible limitduring the first part of the winding `operation so that thedraw-twisting machines according to the prior art are not fully usedsince a lesser amount of yarn is drawn-out and wound up in a given timethan could be wound if the spindles would rota-te at maximumspeeddu'ring the first part of the winding operation.

In accordance with the present invention, the rotary speed of thespindles is adjusted, controlled or regulated, so that the maximumou-tput of the machine can be achieved. The speed of the spindle isvaried in such a manner that the tension of the yarn is maintained atpredetermined desired values which may follow ia certain function, orwhich may be a constant tension.

In lthe embodiment of FIGS. la, lb and 2, the rotary speed of thespindles iis regulated in accordance with a program represented by thecard shown in FIGS. 5a and 5b, and the variation of the Irotary speed ofthe spindle over the time of winding is represented by the graph shownin FIG. 5c.

The electric motor 26 of the spindle drive means includes a servo-motorby which a device for adjusting the position of the brushes of motor 26is operated to gradually and continuously adjust the rotary speed ofmotor 26 and thereby of drive shaft 27.

A gear transmission 81 drives a tachometric means 82 which produces anelectric signal whose voltage is proportionate to the rotary spindlespeed. Two terminals 83 and 84 secure conductors 87 and 90 whichrespectively lead to an indicator 89 and to a comparison device 91 ofknown construction. The spindle speed is indicated by indicator 89 tothe operator.

Program controlled means 94 are provided for sensing a program carryingcard 97, and produce a second signal whose voltage is proportionate tothe desired rotary speed at any time during the winding operation. Thesignal is supplied through conductor 92 to comparison device 91 andcompared with the signal from the tachometric means 82 which representsthe actual value of the rotary speed. The comparison device 91 comparesthe actual value with the programmed desired value of the speed, and ifthe two values are not identical, a command signal is produced andtransmitted through conductor 96 to servomotor Si) to adjust the rotaryspeed of the motor 26. Motor 26 is adjusted until the difference betweenthe actual speed and the programmed speed is below a predetermined smallvalue, which is zero for all practical purposes but is selected toprevent hunting.

As best seen in FIGS. a and 5b, the program carrying card 97 has at itsupper edge a rack 99a whose gear teeth are engaged by a transportingroller, not shown, so that card 97 is continuously advanced during awinding operation.

Card 97, which is made of a synthetic plastic material, has livelongitudinal columns 991) to 99f of which columns 99C to 99j have ridgesof different lengths and spacing, while column 99h has one continuousridge.

The ridges represent in a certain sense orders of desired rotary speeds.For example, the column 99h is associated with 6,000 revolutions perminute, column 99e is associated with 1,000 revolutions per minute,column 99d is associated -with 500 revolutions per minute, column 99e isassociated with 320 revolutions per minute, and column 99f is associatedwith 160 revolutions per minute.

T he number of revolutions at any moment of the winding operation isrep-resented by the ridges located in a line across the card. Forexample, at the line (1, ridges are provided in all tive columns, andconsequently a sens- .ing feeler 98 located across the card, willproduce a signal whose voltage represents a number of revolutions whichis 6,000-|1,000+500+320+160, which are 7,980 revolutions per minute.When the card has traveled further, and the sensing feeler is at theline b, the program voltage represented by the card is 6,000-i-500-i-320which are 6,820 revolutions per minute. The program determined rotaryspindle speeds are represented in FIG. 5c by the number of revolutions nover the time of winding t. It will be seen that in accordance `with thefunction represented by the graph of FIG. 5c and by the program on card97, the rotary speed of the spindle is reduced during the first part ofthe winding operation lasting to the time I2, then maintained at aconstant level to the time t3, and then increased again to the time t4of the end of the winding operation.

The stepped graph 99m represents the effective values, and the brokenline graph 99p represents average values.

The function represented by the graphs of FIG. 5c is empiricallydetermined and results in wound packages having the desired tension inall layers, while the yarn is not unduly stretched during operation ofthe machine at very high winding speeds.

In accordance with conditions prevailing during a drawing-out andtwisting operation, the technological and physical properties of theyarn, and the desired properties of the wound package, the program maybe modified to achieve the desired result. However, at least during thefirst part of the winding operation, the rotary spindle speed isgradually reduced, and it has been found advantageous to operate thespindles at a substantially constant speed during the middle part of thewinding operation. The increase of the winding speed at the end of thewinding operation as described with reference to FIG. 5c, may not benecessary and in this event the winding is preferably carried out at aconstant speed to the end of the winding operation.

It will be understood that at the time t1 indicated in FIG. 5c, thebobbin is empty an-d that the diameter of the wound package continuouslyincreases during the winding operation while the rotary speed of thespindle is reduced. The diameter of the package continues to increasewhile the rotary speed of the spindle is maintained at a constant level,or again increased as described with reference to FIG. 5c.

In the embodiment described with reference to FIGS. la, lb, 2 and 5a to5c, the rotary spindle speed is regulated in accordance with a program.It is, however, in certain cases sufficient to control the speed of thespindles in accordance with a program, and such a simplified arrangementis illustrated in FIG. 3.

The drive motor 26, and the adjusting means with servo-motor correspondto the embodiment described with reference to FIG. 2. However, thecomparison device is omitted, and the program controlled means 102 withsensing feeler 105 produce a voltage signal by sensing the program oncard 104, and such signal, which represents the speed of the spindle inaccordance with the program, is supplied to the servo-motor 80 whichcorrespondingly adjusts the motor speed.

FIGS. 6a and 6b illustrate a program card 104 used in the programcontrolled means 102. A rack 106 is provided along one longitudinal edgeof the card so that the card can be transported by a suitable gearroller. Three columns 10561, 105]) and 105C contain ridges, column 105ahaving spaced ridges 105m, and column 105b having a single ridgeextending along the length of the card. The ridge of column 105C iscontinuous, but shorter than the ridge of column 105b.

In contrast to the card described with reference to FIGS. 5a and 5b, theseveral ridges of the card 104 are not all associated with the rotaryspindle speed. The ridge in column 105C controls the start and stoppingof the twisting machine, which will be operative as long as the ridge incolumn 105C is sensed by the sensing feeler 105.

The several ridges 105m in column 105a and the ridge in column 105b areassociated with the speed control. Whenever the sensing feeler engagesone of the ridges 105m the servo-motor S0 is energized to actuate theadjusting means so that the speed of motor 26 is varied for apredetermined amount, for example 35 revolutions per minute. Thisadjustment is additive and results in a speed increase if no ridge isprovided in column ItiSb in the respective transverse line in which thesensing feeler operates, and is negative if a ridge portion is presentin the respective part of column 105i). For example, along the line (1,a ridge projection is provided in col-umn 105a, and a ridge is providedin column 10517 so that servomotor 80 is controlled to effect a speedreduction of the motor 26 for 35 revolutions pe-r minute, as indicatedby the steps of the graph in FIG. 6c. In the example of the controlfunction represented by the program of the card shown in FIG. 6a, thespindle speed is not increased at the end of the winding operation, butmaintained at a constant level between the time t3 and t4 at the timet3, the control by the program card is terminated so that the apparatusis only used for reducing the rotary spindle speed during the rst partof the winding operation corresponding to the increasing diameter of thebobbin package. Since the spindle speed is not to be increased, ridge1t35b extends along the length of the card without interruption.

The function represented by the graph in FIG. 6c is also characteristicfor a winding operation in accordance with the present invention. Othercharacteristic functions according to other programs are illustrated bygraphs 119, 120, and 121 in FIG. 7. The ordinate again represents therotary spindle speed expressed in revolutions per minute, and theabscissa represents the winding time t. t1 is the start, and t4 is theend of the winding operation.

The function represented by graph 119 corresponds to a grad-ualreduction of the speed of the spindles at a varying rate. During thefirst part of the winding operation, the rotary spindle speed isgradually reduced in accordance with a non-linear function at thegradually reduced rate. In the time period between the times t2 and t3,the function is substantially linear, whereas after the time tgl, thespindle speed is maintained at a constant level to the end of thewinding operation.

It has been 'found that in many cases a non-linear function representedby the program, can be replaced by corresponding linear functions, asindicated at 12). A further variation is indicated by the graph 121 andrepresents an increase of the rotary spindle speed at the end of thewinding operation as described with reference to FIG. 5c. It has beenfound that the yarn wound in the package shrinks to a greater extent inthe inner layers of the package, and relaxes in the outer layers of thepackage where the diameter is greater. By increasing the spindle speedat the end of the operation, the outer layers are wound at a desiredhigher tension. Graph 121 is merely illustrative, and the amount bywhich the spindle speed is increased at the e-nd of the operationdepends on the prevailing conditions and is empirically determined.However/the increase of the spindle speed will be generally producedonly during the last third of the winding operation.

The above described embodiments of the invention use a program carrier,which has been described as a cardV provided with ridges, of whichevidently a perforated card or tape can be substituted` However, insteadof controlling the machine operations by a program carrier, a mechanicalswitching mechanism may be used.

An embodiment of a mechanical switching mechanism for controlling thespindle speed as illustrated in FIG. 9. FIG. 9 only i-llustrates thecontrol mechanism, and the other parts of the machine correspond toFIGS. la, 1b,

kand 2. The drive motor 26 kdrives through a drive shaft the spindles onwhich the bobbins are located, and the yarn is supplied as describedwith reference to FIG. lb.

An adjusting means for motor 26 includes a servo-motorl 80 which,whenever, energized, will adjust the motor speed, and thereby the rotaryspeed of the spindles. Servomotor 8) is connectedl by conductor 123 andconductor 124 to a voltage source 125, a switch 126 being provided inconductor 124 `and adapted to interrupt the connection between thevoltage source and servo-motor 80.

A synchronous motor 130 drives through a reduction transmission 127including gears 137 and 13S, a cam disk or switch actuator 132 to whicha plurality ofcam lugs 133 are detachably attached. Cam lugs 133cooperate with a projection 135 of switch 136 to close switch 136whereby the servo-motor 80 is energized, and the speed of the motor 26is adjusted.

Whenever a cam lug 133 closes switch 136, the rotary speed of motor 26is reduced the same amount, for eX- ample 50 revolutions per minute. Aprogram is selected -by placinly a selected number of cam lugs atselected positions circumferentially spaced from each other on the outerperiphery of disc 132. lBy exchanging gears 138, 137, the rotary speedof cam 132, 133 can be adjusted and the time during which a programrepresented by cam 132, 133 is carried out, can be varied.

Generally, one full rotation of cam disc 132 will correspond to the timerequired for the program-controlled winding operation. However, aprogram may be carried out while disc 132 performs several revolutions.

In the above described embodiments, the rotary speed of the spindles isvaried in accordance with a program which is empirically determined. Inthe embodiment of FIG. 4, the rotary speed of the spindles is regulatedin accordance with the tension of the yarn which is supplied from thedevice 18, to the bobbin 23.

A sensing means 140 of known construction includes a feeler engaging theportion of the yarn between roller 18 and thread guide 47, and means forproducing a voltage signal proportionate to the sensed tension. Thesignal produced by sensing means 140 passes through a conductor 141 to acomparison device 142 of known construction which is provided with anadjusting knob by which the comparison device 142` can be set to aselected constant voltage which is compared with the voltage of thesignal produced by sensing means 140. In this manner the actual tensionof the yarn is compared with a desired constant tension, and acorresponding command signal representing the difference between thedesired value and the actual value of the tension is transmitted throughconductor to a servo-motor by which a gradually variable transmission152 is set to different transmission ratios. Transmission 152 `is drivenby pulley means 159 and a belt 160 from the drive motor 26.

From this condition, the comparison device can be switched by a switchy145 to a condition in which the signal produced yby the Isensing means140 is compared with a signal vsupplied. through a conductor 149 to thecomparison device 142. A program controlled rneans 146 is controlled bya program tape, or by a card as described with reference to FIG'. v5a toproduce a signal whose voltage varies in accordance with selectedprogram during the winding operation so that the differential commandsignal transmitted to servo-motor 170 represents the difference betweenthe tension desired in accordance with a predetermined program at anymoment of the winding operation,` and the actual tension sensed bysensing means 140. In this manner, the tension of the wound-up thread isregulated `during the winding operation to follow a predeterminedfunction.

The tension between device 18, 20 Aand the thread guide 47 depends onthe speed at which traveler 21 runs around twisting ring 35. The greaterthe speed of the traveler is, the greater is the tension of the yarn.The traveling speed of traveler 21 increases when the rotary speed ofthe spindle, and the diameter of the package increase. In the event thatthe rotary speed of the spindle remains constant during the entirewinding operation, the thread tension will increase as the diameter ofthe package increases, and will become a multiple of the tensionprevailing at the beginning of the winding operation with the emptybobbin. This undesired increase of the yarn tension on the bobbin isprevented by the apparatus of the present invention, since the thread.tension is regulated in accordance with a predetermined selectedfunction if the comparison device is used together with the programcontrolled means 146, or the yarn tension is maintained at a constantlevel when the signal of the sensing means i-s compared with theconstant voltage and the control of knob 144.

In any event, the ratio of the transmissionmeans 152 is continuouslyadjusted by servo-motor 170 so that the tension of the yarn correspondsto the desired valuewhich may be a constant value, or a value varying inaccordance with a desired function. The actual tension of the yarn vwillduring the entire winding operation substantially correspond t-o apredetermined tension. A

A drawing-out and twisting machine to which theV present invention isapplied has a great number of spindles.

FIG. 4 illustrates only a single spindle driving arrangement with theassociated drawing-out means. It is not necessary to provide a sensingmeans, and operation control means including a comparison device foreach spindle station of the machine, but by sensing the tension of theyarn wound on one spindle, sufficient information for adjusting therotary yspeed of all spindles is obtained. Therefore, drive shaft 27 isconnected by gear transmission means of the type indicated at 401 inFIG. 2, to all spindles of the machine, for example as illustrated inFIG. 4 by pulley means 28 and lbelt means 57.

FIG. 8 is a diagram illustrating ythe functions according to which thetension of the yarn may be controlled. The ordinate lrepresents the yarntension, and the abscissa represents the time of the winding operation.Graphs 180, 18.1 and 182 represent characteristic functions of the yarntension during the winding operation. The line 181 represents a constantyarn tension, which may be achieved by setting knob 144 of comparisondevice 142 to a desired yarn tension. The graphs and 182 representfunctions determined by programs represented by record carriers orrecord carrying cards, but it will be understood that other functionsmay be selected to be represented by a program carrier. The actualselected function will depend on the weight and material of the yarn, onthe type and Weight of the traveler, on the shape and diameter of thetwisting ring, on the diameter and size of the package, and otherconstructive features, so that it is best to determine empirically theprogram by which a package having the desired properties is produced.The program based on a gradually increasing yarn tension as representedby graph 182 will compensate for a certain relaxing of the yarn in theouter layers of the package, whereas the program producing a graduallylowered yarn tension as represented by graph 180 will have the advantageof a tighter inner core of windings of the package.

The embodiment of FIG. 4 produces the most exact approximation of theactual yarn tension to the programmed tension. However, in many cases itis suflicient to use the yarn tension adjusting apparatus described withreference to FIGS. 2, 3 and 9 to produce packages wound in the desiredmanner by merely programming the rotary speed of the spindles.

In order to achieve a substantially constant yarn tension as representedby the graph 181, it is necessary to continuously reduce the rotaryspeed of the spindles as indicated, for example, by the graph 119 inFIG. 7.

A particularly rigid package is obtained when the yarn tension lisreduced in accordance with the graph 180. When the tension of the innerlayers of the package is greater than the tension of the outer layers,the slipping of windings of the outer layers into spaces betweenwindings of the inner layers, which particularly may occur during thewinding off of yarn from the package, is prevented. By increasing yarntension as the winding operation progresses, as exemplified by graph182, the relaxation of the outer layers of the yarn is substantiallycornpensated. To obtain a function of the yarn tension as represented bygraph 182, it is generally necessary to first reduce the rotary speed ofthe spindles, and then increase the same again near the end of thewinding operation as indicated by the graph portion 121 in FIG. 7.

From the above description of several embodiments of the invention, itwill become apparent that in accordance with the method of theinvention, the rotary speed of the bobbins, and the winding speed of theyarn is automatically varied to maintin the tension of the yarn atpredetermined desired values while the diameter of the packageincreases. Such predetermined value may either be a constant yarntens-ion, or ya-rn tensions varying in accordance with a predeterminedfunction.

It will be understood that the yarn tension adjusting apparatus of theinvention comprises adjusting means,

including a servo-motor 8() for adjusting the speed of the drive means26 and thereby the rotary speed of the spindles and the winding speed ofthe yarn. Operation control means may include a comparison device 91 andprogram controlled means 94, or be of a simpler construction and includeonly program control means for influencing the servo-motor 80 by therecords of a program card 104.

While in the embodiment of FIG. 2, the comparison device receives asignal representing the rotary speed of the spindles, in the embodimentof FIG. 4 the control signal Arepresnts the tension of the yarn.

It will be understood that each of the elements described above, or twoor more together, may also nd reveal the gist of the present inventionthat others can by applying current knowledge readily adapt it forvarious applications without omitting features that, from the standpointof prior art, fairly constitute essential characteristics of the genericor specific aspects of this invention and, therefore, such adaptationsshould and are intotended to be comprehended within the meaning andrange of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. A method for draw-twisting a yarn comprising the steps of drawing outa yarn; rotating a bobbin and winding the drawn-out yarn on the bobbinso that a portion of the yarn supplied to said bobbin is tensioned, as aya-rn package of increasing diameter is formed on said bobbin; producinga first signal representing the rotary speed of said bobbin; producing asecond signal in accordance with a predetermined function of the rotaryspeed of the bobbin over the winding time required for maintaining adesi-red tension of the yarn; comparing said first and second signalsand producing a differential command signal; and automatically adjustingthe rotary speed of said bobbin in accordance with said command signaluntil said lirst signal is substantially equal to said second signal soas to maintain the tension of the yarn at predetermined desired valueswhile the diameter of the package on the bobbin increases during thewinding operation.

2. A method for draw-twisting a yarn comprising the steps of drawing outa yarn; rotating a bobbin and Winding the drawn-out yarn on the bobbinso that a portion of the yarn supplied to said bobbin is tensioned, as ayarn package of increasing diameter is formed on said bobbin; sensingthe tension of the yarn; comparing the sensed tension with apredetermined desired tension; and auto matically regulating the rotaryspeed of the bobbin until the sensed tens-ion is substantially equal tosaid predetermined tension so as to maintain the tension of the yarn atpredetermined desired values while the diameter of the package on thebobbin increases during the winding operation.

3. A method for draw-twisting a yarn comprising the steps of drawing outa yarn; rotating a bobbin and winding the drawn-out yarn on the bobbinso that a portion of the yarn supplied to said bobbin is tensioned, as ayarn package of increasing diameter is formed on said bobbin; comparingthe actual rotary speed of the bobbin with a program representing apredetermined characteristic function of a rotary bobbin speed over thewinding time; and automatically regulating the lrotary speed of thebobbin until the bobbin speed is substantially equal to the programrepresented speed so as to maintain the tension of the yarn atpredetermined desired values while the diameter of the package on thebobbin increases during the wind- -ing operation.

4. A method for draw-twisting a yarn comprising the steps of drawing outa yarn; rotating a bobbin and winding the drawn-out yarn on the bobbinso that a portion of the yarn supplied to said bobbin is tensioned, as ayarn package of increas-ing diameter is formed on said bobbin; andautomatically controlling the rotary speed of the bobbin in accordancewith a program representing a predetermined characteristic function ofthe rotary speed of the bobbi-n over the winding time so as to maintainthe tension of the yar-n at predetermined desired values while thediameter of the package on the bobbin increases during the windingoperation.

5. A method for drawtwisting a yarn comprising the steps of drawing outa yarn; rotating a bobbin and winding the drawn-out yarn on the bobbinso that a portion of the yarn supplied to said bobbin is tensioned, as ayarn package of increasing diameter is formed on said bobbin; producinga first signal representing the rotary speed of said bobbin; producing asecond signal in accordance with a program representing a predeterminedfunction of l the rotary speed of the bobbin over the winding timerequired for maintaining a desired tension of the yarn; comparing saidlfirst and second signals and producing a differential command signal;and automatically adjusting the rotary speed of `said bobbin inaccordance with said command signal until said rst signal issubstantially equal to said second signal; and automatically varying therotary speed of the bobbin to maintain the tension of the yarn atpredetermined desired values while the diameter of the package on thebobbin increases during the winding operation.

6. A method for draw-twisting a yarn comprising the steps of drawing outa yarn; rotating a bobbin and winding the drawn-out yarn on the bobbinso that a portion of the yarn supplied to said bobbin is tensioned, as ayarn package of increasing diameter is formed on said bobbin; andautomatically varying the .rotary speed of the bobbin to maintain thetension of the yarn atpredetermined desired decreasing values during thefirst part of the winding operation while the diameter of the `packageon the bobbin increases.

7. A method for draw-twisting a yarn comprising the steps of drawing outa yarn; rotating a bobbin and winding the drawn-out yarn on the bobbinso that a portion of the yarn supplied to said bobbin is tensioned, as ayarn package of increasing diameter is formed on said bobbin; andautomatically varying the rotary speed of the bobbin to maintain thetension of the yarn at predetermined desired increasing values while thediameter of the package or thebobbin increases during the last p-art ofthe winding operation.

8. A method for draw-twisting a yarn comprising the steps of drawing outa yarn; rotating a bobbin and Vwinding the drawn-out yarn on the bobbinso that a portion of the yarn supplied to said bobbin is tensioned, as ayarn package of increasing diameter is formed on said bobbin; andautomatically varying the rotary speed of the bobbin in accordance witha linear function of the rotary bobbin speed over the winding time atleast during part of the winding operation to maintain the tension ofthe yarn at'predetermined desired values while the diameter of thepackage on the bobbin increases during the winding operation.

9. A method for draw-twisting a yarn comprising the steps of drawing outa yarn; rotating a bobbin and winding the drawn-out yarn on the bobbinso that a portion of the yarn supplied to said bobbin is tensioned, as ayarn package of increasing diameter is formed on said bobbin; and atfirst automatically varying the rotary speed of the bobbin to maintainthe tension of the yarn at predetermined desired values while thediameter of the package on the bobbin increases during the windingoperation, and then maintaining a constant rotary bobbin speed duringthe last part of the winding operation.

10. A method for draw-twisting a yarn comprising the steps of drawingout a yarn; rotating a bobbin and winding the drawn-out yarn on thebobbin so that a portion of the yarn supplied to said bobbin istensioned, as a yarn package of increasing diameter is formed on saidbobbin; and automatically varying the rotary speed of the bobbin inaccordance with a non-linear function or" the rotary bobbin speed overwinding time at least during part of the winding operation to maintainthe tension of the yarn at predetermined desired values while thediameter of the package or the. bobbin increases during the windingoperation.

11. A method for draw-twisting a yarn comprising the steps of drawingout a yarn; rotating a bobbin and winding the drawn-out yarn on thebobbin so that a portion of the yarn supplied to said bobbin istensioned, as a yarn package of increasing diameter is formed on saidbobbin; automatically reducing the rotary speed of the bobbin at thebeginning of the winding operation in such a manner that a minimumrotary speed is reached during the second half ofthe winding timerequired for winding the package l@ whereby the tension of the yarn ismaintained at predetermined ditferent values as the diameter of thebobbin increases during the winding operation.

12.. A method as set forth in claim 11 wherein the minimum rotary bobbinspeed is produced in the time period between two-thirds andthree-quarters of the winding time.

13. A method as set forth in claim 11 wherein the minimum rotary bobbinspeed is between 50 percent and 90 percent of the maximum bobbin speed.

14. A method as set forth in claim 11 wherein the rotary bobbin speed isreduced from a maximum speed to a minimum speed at a graduallydecreasing rate.

15. A method for draw-twisting a yarn comprising the steps of drawingout a yarn; rotating a bobbin and winding the drawn-out yarn on thebobbin so that a portion of,

the yarn supplied to said bobbin is tensioned, as a yarn package ofincreasing diameter is formed of said bobbin; automatically reducing therotary speed of the bobbin at the beginning of the winding operation insuch a manner that a minimum rotary speed is reached during the secondhalf of the winding time required for winding the package, andautomatically increasing the rotary bobbin speed at the end of thewinding operation whereby the tension of the yarn is maintained atpredetermined different values as the diameter of the bobbin increasesduring the winding operation.

16. A method for draw-twisting a yarn passing from a drawing-out devicethrough a thread guide and a traveler on a twisting ring to a bobbin ona rotating spindle comprising the steps of drawing-out the yarn on thedrawingout device; rotating said spindle so that the drawn-out yarn iswound on said bobbiny and the portion of the drawn-out yarn between saiddevice and said thread guide is tensioned as a yarn package ofincreasing diameter is formed on said bobbin; and automatically varyingthe rotary speed of said spindle and thereby of said bobbin inaccordance with a program representing a predetermined characteristicfunction of the rotary speed of the bobbin over the winding time tomaintain the tension of the yarn at predetermined desired values whilethe diameter of the package on the bobbin increases during the windingoperation.

17. Yarn tension adjusting apparatus for a draw-twisting machinecomprising, in combination, a drawing-out device; a rotary spindleadapted to support a bobbin; a twisting ring surrounding said spindle,and a traveler mounted for movement along said twisting ring; a sensingmeans for sensing the tension of the yarn between said device and saidbobbin, and adapted to produce a signal proportionate to the sensedtension; drive means operatively connected with said 'spindle forrotating the same so that the yarn supplied from said device throughVsaid traveler to said bobbin is wound up on said bobbin to form apackage of gradually increasing diameter; adjusting means for adjustingthe speedof said drive means and thereby the rotary speed of saidspindle and the speed of said traveler; and operation control meansincluding a comparison device connected to said sensing means forreceiving said signal, means for producing in said comparison device acomparison signal corresponding to a selected tension, said comparisondevice producing a command signal representing the difference betweensaid signals and thereby the deviation of the sensed actual tension froma desired selected tension and `being connected to said adjusting meansfor actuating the same in accordance with said command signal so thatthe rotary speed of said spindle is varied during the winding operationin such a manner that the tension of the yarn between said bobbin andsaid device is maintained at said selected tension while the diameter ofsaid package increases during the winding operation.

18. Yarn tension adjusting apparatus for a draw-twisting machineVcomprising, in combination, a drawing-out device; a rotary spindleadapted to support a bobbin; a twisting ring surronuding said spindle,and a traveler mounted for movement along said twisting ring; a sensingmeans for sensing the tension of yarn between said device and saidthread guide and adapted to produce a signal proportionate to the sensedtension; drive means operatievly connected with said spindle forrotating the same so that the yarn supplied from said device throughsaid traveler to said bobbin is wound up on said bobbin to form apackage of gradually increasing diameter; adjusting means for adjustingthe speed of said drive means and thereby the rotary speed of saidspindle and the speed of said traveler and operation control meansincluding a comparison device connected to said sensing means forreceiving said signal, means for producing in said cornparison device acomparison signal in accordance with a program representing selecteddifferent tensions desired during different parts of the windingoperation, said comparison device producing a command signalrepresenting the diierence 'between said signals and thereby thedeviation of the sensed actual tension from the desired tension selectedin accordance with the program, said comparison device being connectedto said adjusting means for actuating the same in accordance with saidcommand signal so that the rotary speed of said spindle is varied duringthe winding operation in such a manner that the tension ofthe yarnbetween said bobbin and said device is maintained in accordance with theprogram at predetermined desired values while the diameter of saidpackage increases during the winding operation.

19. Yarn tension adjusting apparatus for a draw-twisting machinecomprising, in combination, a drawing-out device; a rotary spindleadapted to support a bobbin; a twisting ring surrounding said spindle,and a traveler mounted for movement along said twisting ring; a threadguide disclosed between said device and said spindle; a sensing meansfor sensing the tension of the yarn between said device and said threadguide, and adapted to produce a signal proportionate to the sensedtension; drive means operatively connected with said spindle forrotating the same so that the yarn supplied from said device throughsaid thread guide and said traveler to said bobbin is wound up on saidbobbin to form a package of gradually increasing diameter; adjustingmeans for adjusting the speed of said drive means and thereby the rotaryspeed of said spindle and the speed of said traveler; and operationcontrol means for automatically actuating said adjusting means andincluding a comparison device connected to said sensing means forreceiving said signal, and means for producing in said comparison devicea control signal corresponding to a selected tension, said comparisondevice producing a differential signal supplied to said adjusting meanswhereby said actuating means adjusts the speed of said drive means inaccordance with the differential signal so that the rotary speed of saidspindle is varied during the winding operation in such a manner that thetension of the yarn between said thread guide and said device ismaintained at predetermined desired values while the diameter of saidpackage increases during the winding operation.

20. Yarn tension adjusting apparatus for a draw-twisting machinecomprising, in combination, a drawing-out device; a rotary spindleadapted to support a bobbin; a twisting ring surrounding said spindle,and a traveler mounted for movement along said twisting ring; drivemeans operatively connected with said spindle for rotating the same sothat the yarn supplied from said device through said traveler to saidbobbin is wound up on said bobbin to form a package of graduallyincreasing diameter; adjusting means including an electric servomotorfor adjusting the speed of said drive means and thereby the rotary speedof said spindle and the speed of said traveler; land operation controlmeans including program controlled means adapted to produce a signal inaccordance with a program and `operatively connected with said adjustingmeans for controlling the operation of said adjusting means depending onthe program so IS that the rotary speed of said spindle is varied insuch a manner that the tension of the yarn between said bobbin and saiddevice is maintained at predetermined desired values while the diameterof said bobbin increases during the winding operation.

21. An apparatus as set forth in claim 20 wherein said electricservo-motor is directly connected with said program controlled means andeffects adjustment of said drive means in accordance with said signaland program.

22. Yarn tension .adjusting apparatus for a draw-twisting machinecomprising, in combination, a drawing-out device; a rotary spindleadapted to support a bobbin; a twisting ring surrounding said spindle,and a traveler mounted for movement along asid twisting ring; drivemeans operatively connected with said spindle for rotating the same sothat the yarn supplied from said device through said traveler to saidbobbin is wound up on said bobbin to form a package of graduallyincreasing diameter; adjusting means for adjusting the speed of saiddrive means and thereby the rotary speed of said spindle and the speedof said traveler, a tachometric means driven from said drive means andadapted to produce a control signal proportionate to the rotary speed ofsaid spindle, a comparison device connected to said program controlledmeans and to said tachometric means receiving said signals and adaptedto produce a command signal representing the difference between saidsignals and between a desired speed represented by said program and theactual speed of said spindle, said comparison device being connectedwith said adjusting means for controlling the operation of the same inaccordance with said command signal.

23. Yarn tension adjusting apparatus for a draw-twisting machinecomprising, in combination, a drawing-out device; a rotary spindleadapted to support a bobbin; a twisting ring surrounding said spindle,and a traveler mounted for movement along said twisting ring; drivemeans operatively connected with said spindle for rotating the same sothat the yarn supplied from said device through said traveler to saidbobbin is wound up on said bobbin to form a package of graduallyincreasing diameter; adjusting means including an electric servo-motorfor adjusting the speed of said drive means and thereby the rotary speedof said spindle and the speed of said traveler; and operation controlmeans including program controlled means adapted to produce a signal inaccordance with a program, feed back means for producing a controlsignal proportionate to a physical variable representing an actualcondition varying during a winding operation, a comparison deviceconnected to said program controlled means and to said feed back meansfor receiving said signals and adapted to produce a command signalrepresenting the dilerence between said signals and the deviation of theactual condition from a program represented condition, said comparisondevice being connected in the said adjusting means for controlling theoperation of the same in accordance with said command signal so that therotary speed of said spindle is varied in such a manner that the tensionof the yarn between said bobbing and said device is maintained atpredetermined desired values while the diameter of said bobbin increasesduring the winding operation.

24. Yarn tension adjusting apparatus for a draw-twisting machinecomprising, in combination, a drawing-out device; a rotary spindleadapted to support a bobbin; a twisting ring surrounding said spindle,and a traveler mounted for movement along said twisting ring; drivemeans operatively connected with said spindle for rotating the same sothat the yarn supplied from said device through said traveler to saidbobbin Iis wound up on Vsaid bobbin to form a package of graduallyincreasing diameter; adjusting means including an electric servo-motorfor adjusting the speed of said drive means and thereby the rotary speedof said spindle and the speed of said traveler; and operation controlmeans including program controlled means adapted to produce a signal inaccordance with a program, feed back means including a sensing means forproducing a control signal proportionate to the yarn tension varyingduring a winding operation, a comparison device connected to saidprogram controlled means and to said feed back means for receiving saidsignals and adapted to produce a command signal representing thediiference between said signals and the deviation of the actual yardtension and a program represented yarn tension, said comparison devicebeing connected with said adjusting means for controlling the operationof the same in accordance with said commandsignal so that the rotaryspeed of said spindle is varied in such a manner that the tension of theyarn between said bobbin and said device is maintained at predetermineddesired values while the diameter of said bobbin increases during thewinding operation.

25. A yarn tension adjusting apparatus as set forth in claim 24 whereinsaid drive means include an electric motor, a gradually variabletransmission means driven by said motor, a drive shaft driven from saidtransmission means, and other transmission means connecting said driveshaft with said rotary spindle; and wherein said adjusting means includemeans for varying the ratio of said variable transmission means, and aservo-motor for controlling said last-mentioned means and operativelyconnected to said comparison device and responsive to said commandsignal.

26. Yarn tension adjusting apparatus for a draw-twisting machinecomprising, in combination, a drawing-out device; a rotary spindleadapted to support a bobbin; a twisting ring surrounding said spindle,and a traveler mounted for movement along said twisting ring; drivemeans including an electric motor operatively connected with saidspindle for rotating the same so that the yarn supplied from said devicethrough said traveler to said bobbin is wound up on said bobbin to forma package of gradually increasing diameter; adjusting means foradjusting the speed of said drive means and thereby the rotary speed ofsaid spindle and the speed of said traveler, said adjusting meansincluding means for stepwise varying the rotary speed of said electricmotor, and an electric servo-motor connected to said last mentionedmeans for actuating the same whenever energized; and operation controlmeans including a switch in the circuit of said servo-motor, rotary cammeans, and driving means for driving said rotary cam means at a constantspeed for actuating said switch to cause stepwise variation of the speedof said electric motor in accordance with a predetermined programrepresented by said rotary cam means so that the rotary speed of saidspindle is varied during the winding operation in such a manner that thetension of the yarn between said bobbin and said device is maintained atpredetermined desired values while the diameter of said packageincreases during the winding operation, said rotary cam means includinga disk, and a plurality of cam lugs detachably mounted on said diskspaced selected distances from each other, each cam lug extending aselected distance in circumferential direction so that said switch isoperated in accordance with a program represented by the spacing betweensaid cam lugs, the number of said cam lugs, and the circumferentialextension of each of said cam lugs.

27. In a draw twisting machine, in combination, a winding and twistingapparatus, comprising, rotatable spindle means adapted to support abobbin; twisting means; a support mounting said twisting means forrotating movement around said spindle means; drive means for rotating atleast one of said means so that yarn supplied to said twisting means iswound up on the bobbin to form a package of gradually increasingdiameter; ad-v justing means for adjusting the rotary speed of saiddrive means and thereby the speed of said spindle means and of saidtwisting means; and actuating means including program controlled meansadapted to produce signals in accordance with a program and a comparisondevice adapted to compare these signals with signals derived from saidrotating means and being proportionate to the actual rotary speed ofsaid spindle means so as to determine the relationship between saidsignals, said actuating means being connected to said adjusting meansand controlling the same in accordance with variations of saidrelationship between sai-d signals-so that the rotary speed of said onedriven means is varied in such a manner that the tension of the woundyarn is maintained at predetermined desired values while the diameter ofsaid package on said bobbin increases during the winding operation.

28. In a draw twisting machine, in combination, a winding and twistingapparatus, comprising, rotatable spindle means adapted to support abobbin; twisting means; a support mounting said twisting means formovement around said spindle means; drive means for rotating saidspindle means so that yarn supplied to said twisting means is wound upon the bobbin to form a package of gradually increasing diameter;adjusting means for adjusting the rotary speed of said drive means andthereby the speed of said spindle means and of said twisting means; andactuating means including program controlled means adapted to producesignals in accordance with a program `and a comparison device adapted tocompare these signals with signals derived from said rotating means andbeing proportionate to the actual rotary speed of said spindle means soas to determine the relationship between said signals,

said actuating means being connected to said adjusting means andcontrolling the same in accordance with variations of said relationshipbetween said signals so that the rotary speed of said spindle means isvaried in such a manner that the tension of the wound yarn is maintainedat predetermined desired values While the diameter of said package onsaid bobbin increases during the winding operation.

29. In a draw twisting machine, in combination, a winding and twistingapparatus comprising, rotatable spindle means adapted to support abobbin; twisting means; a support mounting said twisting means formovement around said spindle means; drive means for rotating one of saidmeans so that yarn Supplied to said twisting means is wound up on thebobbin to form a package of gradually increasing diameter; adjustingmeans for adjusting the rotary speed of said drive means and thereby thespeed of said spindle means and of said twisting means; and operationcontrol means including program controlled means adapted to produce asignal in accordance with a program, feed back means for producing acontrol signal proportionate to a physical variable representing anactual condition varying during a winding operation, a comparison deviceconnected to said program controlled means and to said feed back meansfor receiving said signals and adapted to produce a command signalrepresenting the difference betweensaid signals and the deviation of theactual condition from a program represented condition, said comparisondevice being connected with said adjusting means for controlling theoperation of the same in accordance with said command signal so that therotary speed of said spindle is varied in such a manner that the tensionof the yarn between said bobbin and said device is maintained atpredetermined desired values while the diameter of said bobbin increasesduring the winding operation.

30, In a draw twisting machine, in combination, a winding and twistingapparatus, comprising, rotatable spindle means adapted to support abobbin; twisting means; a support mounting said twisting means formovement around said spindle means; drive means for rotating one of saidmeans so that yarn supplied to said twisting means is wound up on thebobbin to form a package of gradually increasing diameter; adjustingmeans for adjusting the rotary speed of said drive means and thereby thespeed of said spindle means and of said twisting means; a tachometricmeans driven from said drive means and adapted to produce a controlsignal proportionate to the rotary speed of said spindle, a comparisondevice connected to said program controlled means and to saidtachometric means receiving said signals and adapted to produce acommand signal representing the difference between said signals andbetween a desired speed represented by said program and the actual speedof said spindle, said comparison device being connected with saidadjusting means for controlling the operation of the same in accordancewith said command signal so that the rotary speed of said one drivenmeans is varied in such a manner that the tension of the wound yarn ismaintained at pre determined desired values while the diameter of saidpackage on said bobbin increases during the winding operation.

31. In a draw twisting machine, in combination, a winding and twistingapparatus, comprising, rotatable spindle means adapted to support abobbin; twisting means; a support mounting said twisting means formovement around said spindle means; drive means for rotating one of saidmeans so that yarn supplied to said twisting means is wound up on thebobbin to form a package of gradually increasing diameter; adjustingmeans for adjusting the rotary speed of said drive means and thereby thespeed of said spindle means and of said twisting means; a sensing meansfor sensing the tension of the yarn between said device and Said bobbin,and adapted to produce a signal proportionate to the sensed tension; andoperation control means including a comparison device connected to saidsensing means for receiving said signal, means for producing in saidcomparison device a comparison signal corresponding to a selectedtension, said comparison device producing a command signal representingthe differ ence between said signals and thereby the deviation of thesensed actual tension from a desired selected tension and beingconnected to said adjusting means for actuating the same in accordancewith said command signal so that the rotary speed of said one drivenmeans is varied in such a manner that the tension of the wound yarn ismaintained at predetermined desired values while the diameter of saidpackage on said bobbin increases during the winding operation.

References Cited UNITED STATES PATENTS 1,412,518 4/1922 Guildford 57-932,682,144 6/1954 Hare 57-93 XR 2,735,257 2/1956 Legard et al. 57-932,785,527 3/1957 Lewellen et al. 57-93 2,885,898 5/1959 Malcolm et al.57-93 XR 2,895,284 7/1959 Dritina 57-93 3,265,476 8/1966 Roberson 57-93XR FOREIGN PATENTS 490,448 8/1938 Great Britain.

490,923 8/ 1938 Great Britain.

491,003 8/1938 Great Britain.

FRANK J. COHEN, Primary Examiner.

D. E. WATKINS, Assistant Examiner.

19. YARN TENSION ADJUSTING APPARATUS FOR A DRAW-TWISTING MACHINECOMPRISING, IN COMBINATION, A DRAWING-OUT DEVICE; A ROTARY SPINDLEADAPTED TO SUPPORT A BOBBIN; A TWISTING RING SURROUNDING SAID SPINDLE,AND A TRAVELER MOUNTED FOR MOVEMENT ALONG SAID TWISTING RING; A THREADGUIDE DISCLOSED BETWEEN SAID DEVICE AND SAID SPINDLE; A SENSING MEANSFOR SENSING THE TENSION OF THE YARN BETWEEN SAID DEVICE AND SAID THREADGUIDE, AND ADAPTED TO PRODUCE A SIGNAL PROPORTIONATE TO THE SENSEDTENSION; DRIVE MEANS OPERATIVELY CONNECTED WITH SAID SPINDLE FORROTATING THE SAME SO THAT THE YARN SUPPLIED FROM SAID DEVICE THROUGHSAID THREAD GUIDE AND SAID TRAVELER TO SAID BOBBIN IS WOUND UP ON SAIDBOBBIN TO FORM A PACKAGE OF GRADUALLY INCREASING DIAMETER; ADJUSTINGMEANS FOR ADJUSTING THE SPEED OF SAID DRIVE MEANS AND THEREBY THE ROTARYSPEED OF SAID SPINDLE AND THE SPEED OF SAID TRAVELER; AND OPERATIONCONTROL MEANS FOR AUTOMATICALLY ACTUATING SAID ADJUSTING MEANS ANDINCLUDING A COMPARISON DEVICE CONNECTED TO SAID SENSING MEANS FORRECEIVING SAID SIGNAL, AND MEANS FOR PRODUCING IN SAID COMPARISON DEVICEA CONTROL SIGNAL CORRESPONDING TO A SELECTED TENSION, SAID COMPARSIONDEVICE PRODUCING A DIFFERENTIAL SIGNAL SUPPLIED TO SAID ADJUSTING MEANSWHEREBY SAID ACTUATING MEANS ADJUST THE SPEED OF SAID DRIVE MEANS INACCORDANCE WITH THE DIFFERENTIAL SIGNAL SO THAT THE ROTARY SPEED OF SAIDSPINDLE IS VARIED